Oracle:如果一行不存在，如何插入

问题描述

在 PL/SQL (oracle) 中插入不存在的行的最简单方法是什么?

What is the easiest way to INSERT a row if it doesn't exist, in PL/SQL (oracle)?

我想要类似的东西:

IF NOT EXISTS (SELECT * FROM table WHERE name = 'jonny') THEN
  INSERT INTO table VALUES ("jonny", null);
END IF;

但它不起作用.

注意:此表有 2 个字段，例如 name 和 age.但只有名字是PK.

Note: this table has 2 fields, say, name and age. But only name is PK.

推荐答案

INSERT INTO table
SELECT 'jonny', NULL
  FROM dual -- Not Oracle? No need for dual, drop that line
 WHERE NOT EXISTS (SELECT NULL -- canonical way, but you can select
                               -- anything as EXISTS only checks existence
                     FROM table
                    WHERE name = 'jonny'
                  )

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